Hello professor, I'm havign a hard time understading where does the yield of 14%, since on the excel is not given nor calculated but its just written in the table 
The yield is the discount rate that makes the price equal to 841. The usual way of getting it using solver. If you do not know how to use solver, you can also get it using goal seek:
1 - change the 14% for any number (e.g. 5%)
2 - In the ribbon "Data", click "What if analysis" "Goal seeker"
3 - Fill the parameters: Set cell C125 to value 841 by changing cell $C$119
Click ok, and you should get 14%
Excel is not allowed during the exam; hence, these types of questions are not assessed in the exam.